The epidemic of excess weight in adults is now a significant factor in both morbidity and mortality in the developed world and some emerging countries. Although children have fewer weight-related problems than adults, overweight children are at high risk of becoming overweight adolescents and adults and, therefore, at greater risk of associated health problems. For this reason, excess weight in the young is becoming a public health priority.

Considerable attention has been directed, during the past decade, to the prevalence and risks of adult obesity. What is now raising substantial interest in the medical press is a global increase in the prevalence of childhood and adolescence obesity. The majority of European countries have prevalence rates of overweight and obesity higher than 10% for 10 years old girls and boys. Of even greater concern is that several countries have rates above 30% as in Greece, Italy or Malta1,2. It is also clear that there are substantial geographical variations in the prevalence with Eastern and Southern European countries having particularly high levels.

The definitions of overweight and obesity in children differ between epidemiological studies, making comparisons of cross-national prevalence data difficult. Recently, a group of world experts of the International Obesity Task Force, a committee of the International Association for the Study of Obesity, developed new standards for children that will ease comparisons of childhood obesity rates and contribute to future surveillance3.

There is still considerable debate about the reasons for the increase. Genetic factors can have a great effect on individual predisposition to obesity; however, genetics alone do not explain the dramatic increase in obesity seen in children in recent years. Looking for another explanation, experts’ attention turns to the classic energy balance equation. Is the amount of calories kids eat in balance with their physical activity? Childhood obesity, just like adult obesity, is the consequence of an imbalance between calories consumed and expended; an imbalance that has resulted from gradual changes in a complex set of social factors that influence how children eat, exercise and play. Only a small percentage of obese children can attribute their problem to endocrine disorder or other underlying physical problem.

Previously it had been assumed, that in children excess weight was benign, a fat child meant a healthy child. Now it is clear that there are several immediate and delayed problems associated with obesity in childhood (Table 1).

Apart from physical and emotional problems arising in childhood, longitudinal studies have demonstrated that teenage obesity is a strong predictor of adult obesity, particularly when the parents are also obese. Obesity also occurs earlier in life, producing not only greater disease risks but also a greater social and economic problem.

Table 1: Potential complications of childhood obesity

Overall
Early physical problems	Type 2 diabetes, early puberty, sleep apnoea, liver problems, hypertension, disorders in blood lipids (triglycerides and cholesterol), arterial changes, gallstones, flat feet.
Early psychological problems	Negative self image, low self esteem, social stigma
Increased risk of adult obesity and its problems, physical, social and psychological	Early onset cardiovascular disorders, metabolic syndrome

Reference: Ebbeling et al., Lancet 2002

For all these reasons, halting the rise in the incidence of excess weight in children is a public health priority.

As with adult excess weight, rather than fight the condition, it would be more effective to prevent it. In a later article, the methods of prevention and the results that may be expected will be considered.

References

• Eufic-site: EU Initiatives - HELENA / IDEFICS
• IOTF (www.iotf.org/childhood/euappendix.htm)
• Livingstone MBE. 2000. Epidemiology of childhood obesity in Europe. European Journal of Pediatrics 159 (Suppl. 1): s14-s34.
• Reilly JJ, Dorosty AR, Emmett PM. 1999. Prevalence of overweight and obesity in British children: cohort study British Medical Journal. 319: 1039.
• Ebbeling CB, Pawlak DB, Ludwig DS (2002). Childhood obesity: public-health crisis, common sense cure. Lancet, 360: 473-82.
• Fruhbeck G. 2000. Childhood obesity: time for action, not complacency. British Medical Journal 320: 328-329.

FOOD TODAY 11/2003